Generally speaking imaging systems, including digital cameras, require separate sensors to scene sensing, IR motion sensing, ultrasonic distance sensing, focus sensing, and dedicated focusing pixels. These separate sensors provide information on object detection, and motion sensing, focusing evaluation, exposure measuring and others. These separate sensors are using separate optics for each function. This increases system size and also introduces residual error between imaging optics and sensing optics.
Some sensors use on-chip focusing pixels (focus detection pixels) to provide focusing information, such as phase detecting auto-focusing pixel in cell phone applications, while a majority of similar cameras use image analysis to evaluation focusing. The phase-detecting focusing pixels use of the image areas on the sensor array to achieve higher focusing speed, while image analysis focusing can have true full resolution with relatively slower focusing.
Therefore, a need exists for an imaging sensor with single imaging optics, which can provide all the functions required by the imaging system.